We ask the AVMA to classify all forms of Ventilation Shutdown (VSD/VSD+) as “Not recommended” in the AVMA Guidelines for the Depopulation of Animals: 2019 Edition.

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The current classification of “Permitted in constrained circumstances” lends credibility to livestock producers’ decisions to use VSD/VSD+ in situations the Guidelines did not foresee or intend, most recently as a cost-saving process during COVID-19.

The AVMA classification of Ventilation Shutdown Plus as a “permitted” method of “depopulation” also implies official veterinary support for this inhumane and inefficient method to kill animals.

Classifying all forms of VSD as “Not recommended” would help prevent livestock producers from taking advantage of AVMA’s position on these techniques.

We believe the majority of AVMA members would not approve of any type of Ventilation Shutdown except as a “last resort” depopulation method. The American Association of Swine Veterinarians (AASV) lists 10 other depopulation methods.

We believe veterinarians and the AVMA have the responsibility to “ensure that animals designated for depopulation experience a rapid loss of consciousness or loss of brain function under the prevailing conditions, and that they are handled in a humane manner before and during their depopulation.”

We believe the AVMA did not intend for any form of ventilation shutdown to be used except in extremely unusual and timely life-threatening situations.

Pig and poultry producers have used Ventilation Shutdown to cheaply and efficiently destroy animals. Use of VSD predates COVID-19, but its application as a strategy to kill unwanted or excess animals backlogged due to COVID-19 expands its usage into an even broader realm.

Reclassifying all forms of VSD as “Not recommended” by the AVMA would help ensure any type of VSD would only be used as a “last resort” option. This classification would also support closer coordination and concurrence with State and/or USDA/APHIS officials before performing any form of Ventilation Shutdown. There are many “preferred” depopulation methods already present in the Guidelines to use in an emergency situation.

We believe reclassifying Ventilation Shutdown (VSD/VSD+) will ensure veterinarians and the AVMA adhere to the Guidelines (page 45): “Attention to questions about the moral status of animals has meant that veterinarians and others involved in depopulation of animals during emergency situations must demonstrate to the public and each other due diligence when discharging their professional responsibilities.”

We also ask the AVMA to clarify the conditions for “acceptable depopulation.” There is considerable confusion between the Guidelines stated objective that “Failure to achieve 100% mortality in depopulation is unacceptable.” and the often-cited requirement of “a > 95% death rate in < 1 hour.” In the the August 15, 2021 JAVMA published study, over 700 pigs remained alive after prolonged exposure to VSD+ and had to be manually killed.

That report clearly shows this form of depopulation does not meet the AVMA Guidelines for Depopulation. If you measure the time to death beginning when VSD+ begins (i.e. barn ventilation systems are closed off and heaters turned on), it exceeds the required time limit of 60 minutes by a mean of 30.4 minutes in nursery pigs (90.4 minutes) and 50.3 minutes in finishing pigs (110.3 minutes), failing to meet both the AVMA’s requirements of “100% mortality” and “95% mortality in less than an hour.”

What reclassifying all forms of VSD as a “Not Recommended” method of animal depopulation means:

The current 2019 AVMA Guidelines for Depopulation definition:

Not Recommended - A1.3 - Not recommended These methods should be considered only when the circumstances preclude the reasonable implementation of any of the preferred methods or methods permitted in constrained circumstances and when the risk of doing nothing is deemed likely to result in more animal suffering than that associated with the proposed depopulation method. Examples of such situations include, but are not limited to, structural collapse or compromise of buildings housing animals, large-scale radiologic events, complete inability to safely access animals for a prolonged period of time, or any circumstance that poses a severe threat to human life or animal populations.” (page 86 2019 AVMA Guidelines for Depopulation)


Classifying all forms of VSD as “Not recommended” would help prevent livestock producers from taking advantage of the AVMA Depopulation Guidelines’ inclusion of these techniques except in truly extreme and life-threatening situations, such as infectious animal disease or zoonotic infection outbreaks, or natural disasters. This classification would also support closer coordination and concurrence with State and/or USDA/APHIS officials before performing any form of Ventilation Shutdown.

There are many preferred and permitted methods for animal depopulation listed in the AVMA and AASV Guidelines that may be used in an emergency. Because there is international objection to any form of Ventilation Shutdown as a depopulation method, we ask the AVMA to join other veterinary and animal welfare organizations and re-classify all forms of VSD as “Not recommended.”

We believe the AVMA did not intend for any form of Ventilation Shutdown to be used except in extremely unusual life-threatening situations. By amending the 2019 Guidelines for Depopulation, the AVMA can clarify this position and ensure animals are not unnecessarily subjected to the inhumane death caused by Ventilation Shutdown. There are several mechanisms the AVMA may use to issue this clarification and re-classification that do not require a complete reassessment or rewriting of the Depopulation Guidelines.


Tell the AVMA to reclassify all forms of killing by heat stroke in its Depopulation Guidelines